All of the pros had steering stabilizers to calm the headshake. On the bomb run (start of the race) I used to see a few of the top pros (Ty Davis, Brian Brown, Destry Abbott) hold the KX500 wide open for a couple of minutes. These guys don't need open sand to reach these speeds, that's why they are pros. Mind you, most of them ran pretty stock engines because of reliability and even if one of them had a motor making way more power, it means nothing in a desert race if you can't even hold the stock bike wide open. That's why I'm not looking for ways to squeeze every bit of power of my bike. Team Green had it figured out and their record showed it. I spend most of my time riding my 500 to improve my skills, and rarely work on it other than maintenance.
I made my why up to the expert class when I was racing 250s back in the early 90s, and still could never come close to holding the bike wide open the ENTIRE bomb run. Let up just once for a split second, and your competition with less power will pass you. Even now, there are 125 two strokes that will come in the top ten overall. Usually a pretty young guy. Imagine how fast you would have to ride a 125 through all of the technical stuff to keep up with all the other bigger motors that can open it up on fire roads and lake beds. Put one of these kids on KX500 and look out!
Sniper, that video is pretty cool. I bought one of those KX500 practice bikes that was Brian Browns. Vibration isn't too bad, but the crank is balanced. The engine has the stock carb (properly jetted), stock reeds and cage, FMF desert pipe, and some mild porting that I haven't seen yet. One of the Team Green mechanics told me to use fresh reeds, new gas, clean air filter, and a fresh spark plug to keep the bike running at it's peak. Of course new tires are more important than making a few more ponies. Reminds me of drag racing when I would see the guy with the ported and polished aluminum heads, trick cam, etc., yet he's running with old spark plug wires or incorrect jetting and gets spanked by a low dollar budget build.